Venlafaxine

Generic Name: Venlafaxine Hydrochloride

Brand Names: Effexor, Effexor-XR

Drug Class: SNRI, Anti-depressant

Similar Class Drugs: Duloxetine, Desvenlafaxine

Available Dosage Forms: Oral tablet (immediate and extended-release), Extended-release capsule

What is Venlafaxine?

Venlafaxine is primarily used in the management of major depression in adults. The upregulation of transporter proteins involved in the uptake of serotonin and norepinephrine results in depressed mood, impaired metabolism, and function.¹

Venlafaxine inhibits transporter proteins and enhances the activity of serotonin and norepinephrine. The resultant rise in the levels of both neurotransmitters causes a significant reduction in depressive symptoms. It is selective for serotonin at lower dosages while a potent regulator for norepinephrine at higher dosages.

It has also been regarded as the first-line treatment for generalized anxiety disorder and a second-line treatment agent for obsessive-compulsive disorder.

Off label indications for Venlafaxine include:¹

– Attention deficit hyperactivity disorder (ADHD)

– Peripheral neuropathy in diabetics

– Hot flashes

– Migraines

– Post-traumatic stress disorder (PTSD)

– Pre-menstrual dysphoria

How to use Venlafaxine?

– The initial dose of 37.5mg is prescribed for all conditions except social anxiety disorder (SAD)

– Recommended starting and maximum dosage is 75mg for SAD

– The maximum dosage of Venlafaxine that can be prescribed is 225mg

– Extended-release tablets should not be crushed, chewed, or dissolved in a liquid.

– Take the capsules or tablets once daily with food

– Dosages should be tapered gradually towards the end of treatment

– Dosage should be reduced by 50% in patients with mild to moderate hepatic impairment.

– Patients with hepatic cirrhosis and severely compromised liver function need a dosage reduction of more than 50%

– Dosage should be titrated by 25% to 50% in patients with kidney impairment

What are the side effects of Venlafaxine?

A significant number of fatalities were noted with Venlafaxine overdosing than with other second-generation antidepressants.²

Common side effects with the use of Venlafaxine:

– Headache

– GI upset

– Sweating

– Nausea

– Dry mouth

– Dizziness

Life-threatening adverse effects caused by Venlafaxine:

– Cardiovascular events²

– Increased risk of preeclampsia in second and third trimesters. It is a category C pregnancy drug.²

– Hyponatremia

– Serotonin syndrome

– Seizures

– Mania

– Hypercholesterolemia

– Tremors

– Anaphylaxis

– Suicidal behavior in children and adolescents

Who should not use Venlafaxine?

– Hypersensitive patients

– Patients with ongoing treatment with MAOIs and other serotonin modulators

– Patients with angle-closure glaucoma¹

Venlafaxine should be used with caution in:

– Pregnant and breastfeeding women

– Children and adolescents

– Suicidal ideation

– Cardiovascular comorbidities

– Hyperthyroidism

– Seizure disorder

– Alcoholism

References

1. Singh D, Saadabadi A. Venlafaxine. [Updated 2020 Nov 3]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK535363/
2. Venlafaxine: more dangerous than most “selective” serotonergic antidepressants. Prescrire Int. 2016 Apr;25(170):96-9. PMID: 27186622.